code: def test_line_dataset():
      c = (
          Line()
          .add_dataset(
              source=[
                  [
                      "product",
                      "2012",
                      "2013",
                      "2014",
                      "2015",
                      "2016",
                      "2017",
                  ],
                  ["Milk Tea", 56.5, 82.1, 88.7, 70.1, 53.4, 85.1],
                  ["Matcha Latte", 51.1, 51.4, 55.1, 53.3, 73.8, 68.7],
                  ["Cheese Cocoa", 40.1, 62.2, 69.5, 36.4, 45.2, 32.5],
                  ["Walnut Brownie", 25.2, 37.1, 41.2, 18, 33.9, 49.1],
              ]
          )
          .add_yaxis(
              series_name="Milk Tea",
              y_axis=[],
              is_smooth=True,
              series_layout_by="row",
          )
          .add_yaxis(
              series_name="Matcha Latte",
              y_axis=[],
              is_smooth=True,
              series_layout_by="row",
          )
          .add_yaxis(
              series_name="Cheese Cocoa",
              y_axis=[],
              is_smooth=True,
              series_layout_by="row",
          )
          .add_yaxis(
              series_name="Walnut Brownie",
              y_axis=[],
              is_smooth=True,
              series_layout_by="row",
          )
          .set_global_opts(
              title_opts=opts.TitleOpts(title="Dataset Line Example"),
              xaxis_opts=opts.AxisOpts(type_="category"),
          )
      )
      assert_equal(c.options.get("series")[0].get("data"), None)
  
file_path: pyecharts/test/test_line.py
imports: from unittest.mock import patch
  from nose.tools import assert_equal, assert_in
  from pyecharts import options
  from pyecharts.charts import Line
label_desc: Use image node_id 6 for calling a global function with example usage: test_line_dataset() without return types